1. Field of the Invention
The present invention relates to a packaging buffer material used to packing an article such as electric product, a mechanical component, a mechanical product, a glass or a pottery. The present invention particularly relates to a packaging buffer material and a method of manufacturing a packaging buffer material capable of being manufactured using a simple mold, being mass produced, being recycled, and facilitating packaging operation.
2. Description of the Background Art
Generally, if an article such as electric product, a mechanical component, a mechanical product, a glass or a pottery is to be packed in a cardboard box, a packaging box or the like, a buffer material is disposed between the packaging box and the article so as not to damage the article. Conventionally, a partition plate consisting of expanded polystyrene resin or thick corrugated cardboard is used as such a packaging buffer material. The partition plate is used by assembling a necessary number of corrugated cardboards corresponding to a shape or a magnitude of the article.
A conventional packaging buffer material is disclosed in, for example, Patent Document 1 (Japanese Utility Model Registration NO. 2607208). FIG. 8 is a schematic diagram showing a conventional packaging buffer material disclosed in the Patent Document 1. In FIG. 8, a packaging buffer material 51 is configured to include a tubular member T consisting of paper or a composite material mainly containing paper and having a generally U-shaped cross section. The packaging buffer material 51 is configured to include a pair of opposed portions 52 and a coupling portion 53 coupling side edges of the opposed portions 52 to each other.
The tubular member T is configured to include a first constituent element 58 having a generally U-shaped cross section, a second constituent element 59 having a generally U-shaped cross section and arranged outside of the first constituent element 58 to be distanced from the first constituent element 58, and two connection circular arc elements 54 having circular arc cross sections and connecting two edges of the first constituent element 58 to those of the second constituent element 59, respectively. Concave grooves 56 and 57 depressed toward the first constituent element 58, i.e., depressed inward of the tubular member T and extending in a length direction are formed in portions forming outer sidewalls 52a of the opposed portions 52 and an outer sidewall 53a of the coupling portion 53 of the packaging buffer material 51 in the second constituent element 59, respectively.
Further, coupling portions 55 coupling portions forming the outer sidewalls 52a of the opposed portions 52 of the tubular member T to a portion forming the outer sidewall 53a of the coupling portion 53 in the first constituent element 59 are formed to have circular arc cross sections, respectively. The packaging buffer material 51 is produced by, for example, winding the composite material consisting of paper or mainly containing paper around a mold having a shape corresponding to that of the packaging buffer material 51 by spiral winding or plane spiral winding. Furthermore, the packaging buffer material 51 is produced by forming a long tubular member using the composite material consisting of paper or mainly containing paper by some method and then cutting off the long tubular member.
However, the conventional packaging buffer material has the following problems. If a strong force is applied to the packaging buffer material from a lateral or longitudinal direction, the paired opposed portions 52a and the outer sidewall 53a are depressed inward. At this time, because of large widths of the concave grooves 56 and 57, the outer sidewalls 52a contact with the respective opposed portions 52 and the outer sidewall 53a contacts with the coupling portion 53. As a result, external pressure may possibly directly damage an article packed in the packaging buffer material 51. Moreover, since both ends of the packaging buffer material 51 are opened, the internal article directly packed in the packaging buffer material 51 may possibly be displaced laterally.